Go to your local NAPA and look on the shelf for their EFI repair kits for things like fuel filters. They will have a compression fitting. You won't even break 80 PSI on any of these systems. I have used one of those before on an older GM car and it never had a single issue...and we're talking years and years later.
If it were brake lines i'd agree with you....but those need to hold at least 30x the pressure.
